A conventional piezoelectric device includes a substrate, a lower electrode layer on a surface of the substrate, a piezoelectric layer, and an upper electrode layer which are stacked in this order. When a voltage is applied to the upper electrode layer, the piezoelectric layer deforms due to an electric field developed between the upper and lower layers, thereby providing the device with a variety of functions.
In the conventional piezoelectric device, however, a stacked structure including the upper and lower electrode layers and the piezoelectric layer has poor strength in bonding with the substrate. Applying the voltage to the upper and lower layers deforms the piezoelectric layer, and this causes stress to the substrate. In the conventional piezoelectric device, the upper and lower electrode layers and the piezoelectric layer, being sized substantially the same, are bonded with the substrate. The poor bonding between the lower electrode layer and the substrate causes them to be peeled off.